Control system



Jan. 9, 1945. c. r. JACOBS 2,367,028

CONTROL SYSTEM Filed Dec. 21, 1940 2 Sheets-Sheet l Let (x-u) -vd (X) l 31 27 i '7: V?

71 3 4 9 Snnentor Cihzrles T Jacobs Bu l g I (Itlorneg Jan. 9, 1945. T JAC S 2,367,028

CONTROL SYSTEM Filed Dec. 21 1940 2 Sheets-Sheet 2 Smaentor attorney Patented Jan. 9, 1945 UNITED STATES PATENT; OFFICE CONTROL SYSTEM 7 Charles '1. Jacobs, New Providence Township, asslgnor in Thomas A. West Orange, N. J., a corporation of New Jersey Application December 21, 1940, Serial No. 871,195

Union County, N. J. n, Inco porated,

Ediso 19 Claims.

This invention relates to control systems, and in many or its principal aspects to such systems of the time-delay type-e. g.. adapted to perform or complete a controlling function at the expiration oi a predetermined interval of delay following an initial manipulation or energizaticn of the system.

In several co-pending applications, all assigned to the assignee of this application, there have been disclosed and claimed control system; of the type abovementioned which include as an operating element an energy-storing device (tor example, a thermal element) and which, in their operation for a second or succeeding time (i. e., in their "recycling) Just as soon as desired after a prior use or incompleted use, served to perform their controlling function with substantially the same interval of delay as when first operated after relatively long periods of disuse. These applications are my co-pending application Serial No. 336,873 now Patent No. 2,272,975 Feb. 10, 1942 (flied May 23, 1940, as a continuation in part of a prior application Serial No. 128,219, flied February 27, 1937); the application of Charles D. Geer, Serial No. 336,894 (filed May 24, 1940); and the application of Charles W. Slocum and myself, Serial No. 340,660 now Patent #2272376 Feb. 10, 1942 (filed June 15, 1940). These applications have respectively eventuated in U. 8. Patents Nos. 2,272,975; 2,272,976; and 2,272,977, each issued February 10, 1942.

In one aspect the systems disclosed in those applications involved. as a control means to be operated, relatively movable control members which, upon any de-energization of the system, were at least substantially immediately restored to a predetermined mutual relationship, so that a subsequent energization of the system, however soon indulged in, found the system in predetermined condition. One oi the objects 01 the instant invention is the improvement and simplification of the means and methods for predetermining the mutual relationship of the control members, appropriately to the full compensation of the system for prior use.

Another object is the provision of means and methods for varying the delay interval of operation of the system, without affecting its compensation for prior use and without necessitating a plurality oi interrelated re-adjustments.

Another object is the provision of a system of the general type disclosed in which excessive accumulation 01' energy in the operating device is automatically avoided.

Another object is the provision of improved and Ill simplified structures and sub-structures for a system oi the general type disclosed.

Another object is the provision of improved and simplified arrangements for compensating the system tor the efl'ects of ambient temperature.

Another object is the provision 01 a system oi this general type which is compensated not only tor prior uses, but also for the variations oi voltage at which the operating current may be supplied thereto.

Another object is the provision oi improved means and methods for voltage compensation oi time-delay systems generally.

Other and allied objects will more fully appear from the following description and the appended claims.

In the descriptionof the invention hereinafter set forth, reference is had to drawings, of which:

Figure l is an elevational view of a control structure, and a schematic view of typical further components which with that structure make up a control system, embodying my invention in one form;

Figure 2 is a similar view illustrating the embodiment of my invention in another form, which in general is preferred when voltage compensation is not to be employed;

Figure 2a is a vertical cross-sectional view, on enlarged scale, taken along the line la-2a oi Figure 2;

Figure 3 is a view of generally similar nature to earlier figures, but illustrating the embodiment of my invention in another form, wherein voltage compensation is provided for;

Figure 4 is a view of generally similar nature to earlier figures, but illustrating the embodiment of my invention in still another form wherein voltage compensation is provided for;

Figure 5 is a view of generally similar nature to earlier figures, but illustrating the embodiment of my invention in still another form, which in general is preferred when voltage compensation is to be provided for; and

Figure 6 is a view of generally similar nature to earlier figures, but illustrating a control structure and system embodying voltage compensation arrangements as in Figure 5 but without prior-use compensation features.

Figure 1 illustrates an embodiment of the instant invention which comprises a re-arrangement 0! the structure of the co-pending application Serial No. 340,660 abovementioned, to-

the accompanying gether with the addition of means for obviating unnecessary overheating and of special provisions for adjusting the delay interval of operation.

Inthisnguretherewfllbeaeenabase I, at the lefthand extremity of which there is provided the upwardly extending stack 2 of insulating blocks. At a relatively low elevation in the stack 2 there is clamped the leftband portion of a short, light spring II. An intermediate portion of this sprin'g H is clamped in another stack II, the pring il serving eflectively to pivotally support the stack l1 to the stock I. To the righthand portion oi the spring ii is secured the lefthand extremity of an arm a. rigid within itseir.

Two bimetallic arms, 3 and ii, have their lefthand extremities clamped in the stack l1, respectively below and above the spring Ii. The bottom bimetallic arm I may be provided with the heater winding l, covered or protected at least on its bottom surface with a covering la, of which the bottom surface is preferably smooth for reasons hereinafter apparent. Also having its lefthand extremity clamped in the stack l1, above the bimetallic arm II, is an arm I! rigid within itself, as well as in its juncture to the stack ii.

To the bottom of the bimetallic arm It, at its righthand extremity (which may be somewhat to the left of the extremities of arm 8 and bimetallic arm 3) may be secured a contact 59. To the arm 9 underneath the contact 50 may be secured a cooperating contact 5|; this contact II is, however, insulated from the arm 9 as by insulation 52 seen both above and below that arm, connection being made to the contact ii at its bottom extremity seen below the lower insulation 52. The arm 9 is biased to upward rotation about stack H by an appropriate stress in the righthand portion oi spring ll; accordingly the contact 52 will normally be held against the contact II, and the position of the arm 9 will normally be determined by that of the bimetallic arm it.

At an intermediate elevation in the stack 2 there is clamped the lefthand portion of another light spring i2. The righthand portion of this spring i2 is clamped in the lower part of a stack l8 (which is thus disposed above and slightly spaced from the stack l1) the spring i2 serving effectively to pivotally support the stack iii to the stack 2. In contact with the spring ii there is clamped in the stack is the lefthand extremity of an arm IB, rigid within itself as well as in its juncture to the stack 18. Above the arm in there is clamped in the stack IS the lefthand extremity of a bimetallic arm i5. This bimetallic arm l5 may be provided with a heater winding 2|, preferably having a covering 2m analogous to the covering of the heater winding 4 on bimetallic arm 3.

In the assembly lt-|6-93 carried by the lower stack l1, the two bimetallic arms (l6 and 3) may be arranged to bow upwardly in their central portions-or downwardly at their free extremities when their other extremities are restrained-with heat. The bimetallic arm ii in the assembly I5-ill carried by the upper stack It may be arranged to bow in the opposite manner. Otherwise the appropriate relations between the three bimetallic arms are two in number: (1) that IS and i8 shall have substantially the same degree of bowing. or self-displacement, per degree of temperature change, and (2) that i! and 3 shall have substantially the same thermal constant, which may be designated as P. (This constant will be understood to be the reciprocal of the so-called time constant Q, and to be equal to the ratio FIG-when 1" is a constant expressing the heat-transfer or cooling facility oi the device, and C is a constant expressing the thermal capacity, or mass times specific heat.) It will be understood, however, that the substantial identity of thermal constant between it and I does not require any particular relationship between their respective heater windings 2i and I or between the respective watts input thereto, as these do not affect the thermal constants.

The effectively pivotal support of the stack ll leaves the righthand extremities of the arms il-iIs-l free for joint up-and-down movement. Underneath the bimetallic arm I there may be provided a vertical stud ll secured in and extending upwardly from the base I; and the resting of the bimetallic arm- I on this stud will provide a second point of support for the assembly H-iiil-l. Actually. of course, it will be the bottom surface of the covering in which rests on the stud, excepting when the stud is positioned underneath the very end portion 0! the bimetallic arm 3; and it is desirable to secure to the bottom of this portion a small shim to whose bottom suriace forms a smooth continuation of that of the covering to. As illustrated in full lines, the stud I3 is positioned underneath the end portion of the bimetallic arm 3 (therefore being borne on by lb) The stud is, however, preferably movable at will leftwardly from this position, for purposes hereinafter explained. Accordingly the portion lid of the stud which passes through and below the base I may be of reduced diameter and threaded, and may be disposed in an elongated slot la in the base along which the stud may be slid to desired position; the stud may be locked in the desired position by tightening nut lib upwardly against the base I,

The assembly i4--l89-3 is employed for moving one of two control members which together form a control means to be operated. In the illustrated embodiment of the invention this control means may be a switch comprising a pair of switch contacts I and 8, typically spaced from each other normally and intended to be closed against each other to complete the control means operation. Contact 1 may be carried by arm 9, preferably on top of the righthand extremity of a very light and small leaf spring la, whose lefthand extremity is secured to arm 9 (for example underneath the upper insulation 52 abovementioned). Contact 8 may be carried, above contact 1, on the bottom oi arrn II). It will be understood, of course, that spring l2, in addition to its supporting function, will form an electrical terminal for the contact 8; and likewise that spring ii, in addition to its like function, will form an electrical terminal for contact I.

The contact 8 is normally maintained in predetermined relationship (predetermined in manner hereinafter more fully discussed) to the contact I. In the illustrated embodiment this is done by means of a tie-rod or -screw i9, having its lower extremity secured in the righthand extreme portion of arm l4, and passing upwardly through oversize holes in arm ill and bimetallic arm ii to carry an adjustable nut 20 above the latter. The spring I! is stressed not only to counteract the influence of the weight which it supports, but also to impart a small net upward bias to bimetallic arm i5, so that it will dependably bear upwardly against the nut 20. The stress of the portion of spring ll between stacks 2 and I! will be so arranged that the total or net bias of the assembly l4--|B93 (reflecting both weight and spring action) will cause the bimetallic arm 3 dependably to contact the stud it! whether or not the tie-screw I9 is exerting an upward urge on that assembly (a small such urge of course being normally transmitted by that screw from the bimetallic arm l5).

It is convenient here to note that ambient temperature will be without effect on the spacing of the contacts 1 and 3 from each other. As ambient temperature increases, contact 1 will be moved, by the bowing of bimetallic arm i6, downwardly relative to the righthand extremity of arm l4. At the same time arm Ill and contact 8 will be moved, by the bowing of bimetallic arm 85, downwardly relative to the righthand extremity of that bimetallic arm and (in view of the tiescrew l9 and nut 20) also relative to the righthand extremity of arm I4. The amplitudes of these movements being equal (in view of the described similarity of self-displacement-perdegree-temperature-change of l5 and IS), the contact spacing remains unchanged.

In further describing, and considering the action of, the structure, it will be convenient to assume-until the matter is again specifically referred to-that the heater winding 2i about the bimetallic arm i5 is not energized. Therefore, so long as the tie-screw I9 is the determinant of the position of the upper assembly l5l0, the spacing between contacts 1 and 8 would not be varied at all.

The main actuating element of the structure is the bimetallic arm 3, or the electro-thermal device formed by that bimetallic arm and its associated heating winding 4. The bimetallic arm 3, in bowing with heat, will proportionately tip the stack I1 angularly, or rotate it, counterclockwise about the spring ll, thereby raising the righthand extremities of |4i69 and thus raising contact 1. But in the absence of further structure, and for reasons Just pointed out, this rise of the stated elements would be without effect on the control means 1-8. As disclosed in the co-pending applications, however, the means which normally maintain contacts 1 and B in predetermined relationship to each other may be rendered inoperative at timestypically simultaneously with the supply of energy to the bimetallic arm 3 (e. g., of current to its heater winding 4). Further as disclosed in those applications, this effect may for example be achieved by rendering stationary the upper contact 8, as by couplin the arm 10 to a stationary object.

A means for such coupling has been illustrated in Figure l. The arm Ill may be extended for a short distance beyond the contact 8, and then folded downwardly for a short distance. To its bottom extremity may be secured a leaf spring 22 extending first downwardly and then curved rightwardly and upwardly, and carrying an armature 23 of magnetic material secured to the outer surface of its upwardly extending portion. An electromagnet 24 may be mounted on a standard 25 extending upwardly from the righthand extremity of the base I, and may have its active pole end 24a positioned very slightly to the right of the normal position of the outer surface 23a of the armature 23. The electrical terminals of the electromagnet 24 may be connected as by leads 26 to current source 3|, through a switch 21. The heater winding 4 about the bimetallic arm 3 may be connected, as through lugs 5 and 3 in stack 2 and by leads 34, to the same source 3| through a switch 28. For the preferredly contemplated case of concomitant energization of the bimetallic arm 3 and coupling of arm ill, the switches 21 and 28 may be arranged for simultaneous operation, as indicated in Figure 1 by the insulating tie 23 therebetween.

It will be understood that upon closure of the switches 21 and 28, there will occur a concomitant energization of the electromagnet 24 and supply of energy to the bimetallic arm 3 (i. e., energizetion of the electro-thermal device 34 formed by that bimetallic arm and its associated winding). The armature 23 will be attracted into intimate contact with the pole end 24a, and its frictional contact therewith will prevent the upward movement of spring 22 and arm HI and contact 8 which would otherwise occur with a rise of the lower elements l4l69. Meanwhile such a rise of those elements occurs, in response to the heating of bimetallic arm 3 and its consequent bowing; and, at a rate predetermined by the parameters of and conditions within the system, that rise will carry the contact 1 upwardly toward and into contact with the contact 8, thus operating the control means 18.

The control members 1 and 8, which normally (or when the electromagnet 24 is not energized) move jointly with each other, may be occupying any absolute mean elevation in response to the then-existing degree of bowing of bimetallic arm 3, when the switches 21 and 28 are closedthe armature 23 being vertically elongated to insure a portion of its face 23a being opposite to the electromagnet pole end 24a under any practical conditions.

When the switch 21 is opened (for example simultaneously with the switch 28)whether that opening occurs before, with, or after the closing of the contacts 1 and 8the armature 23 and spring 22 will be released by the electromagnet 24, and the predetermined relationship of contacts i and 8 will be instantaneously restored under the influence of sprin l2. However soon the switches 2'! and 23 may be reclosed, the armature.23 will simply be attracted to the pole end 24a in a fresh position; and the operation of the system will be repeated, again starting with the contacts 1 and 8 in their predetermined relationship, as described for an initial operation.

The operation of the control device 18, or closure of the normally open switch which that device comprises in the illustrated embodiment, may be utilized for any desired purpose and in any desired manner. Purely by way of example there have been illustrated, connected in series with the terminals (springs) H and 12 for that device, through conductors 34, a current source 32 and load 33-that load accordingly being supplied with current from that source through the control means 1-8 at the expiration of the delay interval following closure of the switches 21 and 28.

According to th preferred embodiment of the instant invention, if the supply of current to the eleotro-thermal device 3-4 be continued appreciably after the operation to. g., closure) of the control means 1B, that supply will be interrupted to obviate excessive overheating of that device. This is the reason for the described mechanical arrangement of the contacts 50 and il. Electrically these contacts may be serially interposed in the connection from the one extremity of the heater winding 4 to the lug 6. Normally these contacts are closed against each other, so that the operation of the structure as described in immediately, preceding paragraphs will not be affected. As the upward movement of the assembly "-46-! is continued after closure or the contact 1 against the now-stationary contact I. the spring in will at first yield, but very shortiy will be precluded from rurther yielding (as by impingement oi its downwardly-folded extremity lb against the arm 9). Then the arm I is prevented rrom joining in the further upward movement the assembly lll69; and the contact Bl will be carried away from the contact II, breaking the supply of current to the heater winding 6. The bimetallic arm 3 will then stop its upward central bowing and will start to reduce that bowinfl, t e assembly lll6-9 accordingly stopping its rise and starting downwardly. But before the contact I is carried away from the contact 8, the contact 58 will have been brought back into closure against contact II, reestablishing the supply of current to the heater winding l, and re-starting an upward bowing of bimetallic arm 3 and upward movement of the mentioned assembly. This will cause a repeated breaking of the supply 01 current to the heater winding l-and this break-and-make action will continue oscillatorily as long as the switch 28 remains closed, this action serving to preclude much more than that degree of heating of the bimetallic arm 3 which is necessary to carry contact I into closure against contact I, and that closure being maintained throughout this action.

Basically, the operations of systems of this improved type, even very quickly repeated after prior operations or incomplete operations, tend be characterized by a uniform delay intervalin distinction to the operations of wholly conventional systems, in which, by reason of lack of counteraction of or compensation for the finite and slow loss of energy from the energy-storing device (e. e., of heat from the thermal actuating device), the delay interval is sharply reduced in the case of quickly repeated operations. In the oo-pending application Serial No. 340,660, however, it was pointed out that there were instances of use of the improved-type systems wherein the operating conditions are sufllciently severe-by way, for example, of number of desired recyclings and rapidity with which they follow each other-to render quite appreciable in magnitude those deviations, from uniformity of interval, which would in more usual cases be of inconsequential magnitude.

The just-mentioned co-pending application pointed out in detail how these deviations, though much reduced and changed in sign from those characterizing wholly conventional systems, still arose by reason of the excess of energy (e. g.. excess temperature over ambient) of the main actuating device at the begnning of a quickly repeated operation. It further disclosed an exent for eliminating them i or reducing them i. iy desired value and sign). This expedient in i moral is the predetermination oi the normal relanonsnip between the control members (the relationship obtaining in between the operations or the system), not at a uniquely fixed value, but inversely (i, e., in an opposite sense) to the excess energy of the main actuating device. It showed that a means of eflecting a correct such predetermination was the use of a secondary energy-storing or electro-thermal device, both supplied with energy and permitted to lose energy in proportion to the supply to and loss from the main actuating device, and for example arranged to reduce the normal spacing between such contacts as I and 8 according to the excess temperature of such a main actuating device as 8-4. It also showed that there should be incorporated ambient-compensating means i'or such a secondary device.

In the instant embodiment of Figure 1, the bimetallic arm II with its heater winding 2i rorms such a secondary device, and the bimetallic arm It forms the ambient-compensating means therefor. The heater winding 2| is connected to receive energy from source 3| through the switch 2! simultaneously with the supply oi energy to the heater winding 4; this may be done by connecting it between the contact 51 and a lug la in stack 2, that lug being connected as by conductor 36a to that one of the leads 3|) which is connected to lug 5. As already pointed out, the bimetallic arm has a similar thermal constant to the bimetallic arm 3, so that their energy losses as well as receipts are at all times proportionate. But the constants of the heater circuit for the bimetallic arm iii are so chosen that its distance of displacement at any time from ambienttemperature position will be a fraction of that or the bimetallic arm 3 at the same time.

Thus if d represents the self-displacement of the end of 3 (or of the electro-thermal device 3|) from its ambient-temperature position (reckoned on the assumption that its other extremity is securely held), dM may express the attendant distance of self-displacement of lb (or 01' the electro-thermal device I 5-H) from its same-ambient position--M being a fraction. And it is convenient to denote as D the value of it when the bimetallic arm 3 has been heated by its heater winding 4 so long that it is essentially incapable of further movement by the same current supply-i. e., the saturation sell-displacement of the electro-thermal device 3-4. Then the saturation self-displacement of the electrothermal device l5--2l is of course DM. (For reasons hereinafter apparent the displacement or the end of bimetallic arm 3 here mentioned will be its displacement at contact I; while the displacement of bimetallic arm i5 here mentioned may be taken as referred to the side-to-side position of the contacts 1 and 8i. e., as the actual displacement of the end of IE multiplied by the slightly-greater-than-unity lever ratio or the length of 3 divided by the length of i5.)

Best to visualize the operation of the instant structure, it is convenient to note the absolute upward displacements of the several elements, from their respective ambient-temperature positions (and referred to the side-to-side position or the contacts 1-8), in terms oi d and M-at present assuming the stud l3 to be in its fullillustrated position underneath the end of the bimetallic arm 3. It is readily seen that these upward displacements are zero for the device 3-4; d for the bimetallic arm 16 and contact I; and d(lM) for the arm Ill and contact 8 at any time when the coupling means is out 01' operation-as noted in the leithand vertical tabulation in Figure 1. It may be noted that the figure ior arm l0 and contact 8 is that for arm l6 and contact 1 reduced by dM-this reduction being effected by the device |52i.

The last-mentioned co-pending application further laid down a quantitative criterion for the full elimination of the deviations above discussed. This criterion is that the relative movement to which the control members must be subjected by the main actuating device (e. g., 3-4) for operation of the control means which they term, reckoned at any instant when the coupling means is placed in operation (or, in such a structure as that of Figure 1, the actual initial separation of the contacts 1 and a from time to time) should be logarithmically varied in the same manner as the excess 01' saturation self-displacement over actual self-displacement of the main actuating device. One end-condition attendant on, and indicating, the embodiment of this criterion is that it, with the coupling means out of operation, the electro-thermal devices are supplied with current so long that they are essentially saturated, the separation of the contacts 1 and a will Just have been reduced to zero. The other end-condition attendant on, and independently indicating, the embodiment of the criterion is that when the electro-thermal devices are at ambient temperature, the contact separation will be equal to the saturation self-displacement oi i5-2l, or equal to DM.

I contemplate the embodiment of this criterion, by adjustment of the nut 20 until either of the stated end-conditions is met under the respectively appropriate condition of the electro-thermal elements. Since to adjust by the second of the stated end-conditions it is necessary to have determined in advance the saturation self-displacement of l5-2i, it may be more convenient to adjust by the first.

The general case of operation of the system is its operation for a variable number, t, 01' seconds, following a prior operation which may be assumed to have been immediately prior and to have been for an independently variable number, v, of seconds. (There may have been no recent prior operation, in which case 1) simply equals zero. On the other hand, there may have been a prior operation not immediately prior, for more than 1: seconds, but causing the electro-thermal elements at the beginning of the t-second operation to be at the same temperatures as an immediately prior v-second operation would have. Thus the assumption of a variable, v-second, immediately prior operation is a perfectly general one.) Resorting to the well-known logarithmic approximation of displacements for devices of this general character (in which e represents the base 01' the Naperian logarithms), the spacing between the contacts at t seconds following the beginning 01 an operation which in turn follows an immediately prior operation for 12 seconds, may be written:

Herein the first term represents the actual initial separation of the contacts; and the bracketed double term represents the rise of the contact 1 during the t-second operation.

The solution of Equation 1 or la for the value of t at which the spacing of the contacts be- (d) of contact 1 comes zero-4. e., at which there occurs contact closure, or operation or the control device-is This shows that t, or the delay interval, is completely independent of the variable u, so that the system is completely compensated for any prior use (as well, of course, as for ambient temperature conditions). This result, though similar to that obtained by the structure 01' the lastmentioned co-pending application, is obtained in the instant case by a structure which has, as a first advantage, obviation of overheating of the electro-thermal devices. (Jther advantages 0! the instant structure will become apparent hereinafter.

It is frequently desirable to be able to alter the delay interval of operation, as conditions or purposes of use of the system may change. The last-mentioned co-pending application did not make any provision for such an alteration; and, broadly. it will be understood that a definite problem is presented by the requirement that any expedient resorted to for such an alteration must leave unimpaired the compensation or the system for its prior use. (Thus for example, the variation of the initial or ambient inter-contact spacing, usually restored to for delay interval alteration in wholly conventional systems, cannot be employed, for it would violate the condition that this spacing be equal to DM.) It is possible, of course, to eflect such an alteration, and yet preserve the prior-use compensation, by appropriately varying some two or more parameter of the system; but (over and above the inherent diiliculty which may attend the variation of any one or more of those parameters) the requirement that each of the parameters be varied in some proper relationship to the variation in the other is a very burdensome one. What is most highly desirable is an expedient for altering the delay interval by varying some one parameter. this variation not upsetting the alreadyeiTected adjustment of the system for prior-use compensation, and requiring no attendant readiustment of any other parameter.

I have discovered that with either the structure of the last-mentioned co-pending application or the instant structure, an expedient of the desired character for delay interval variation consists in the variation of the energy or watts input to the main actuating device (e. g., the electro-thermal device 3-4), the input to the secondary device (e. g., the electro-thermal device i52i) meanwhile being kept as before. It is for this reason that I have shown separate lugs ii and 5a respectively for one terminal of the heater winding 4 and for one terminal of the heater winding 2|, and a current-supply lead 30a peculiar to the lug 5a. In the part of conductor 30 peculiar to lug 5 I have shown serially inserted a variable resistance 49.

It will of course be understood that variation of the watts input to the electro-thermal device 3-4, as by variation of the resistance of 49, will vary the displacements of that device-that is, its self-displacement at any instant, and its saturation self-displacement, proportionately. (Thus it may be shown that the saturation self-displacement of that device, or D, is proportional to approximately EK/F', when E is the watts input, K is the self-displacement-per-degree-temperature-change of the device, and F is the abovementioned heat-transfer or cooling facility of the device.) It is convenient to assume that d (and its saturation value D) abovementioned expresses the self-displacement 8-4 when resistance ll is adjusted to zero value (and that II was so adjusted throughout the operation of the structure as considered up to this point). To indicate the enect of all possible adjustments or 0, the sell-displacement of 3-4 may be taken as dz (saturating at DZ), when Z is a fraction indiand its solution, analogous to Expression (2), is

Herein it will be seen that variation of Z (by variation 01' ll) will alter the delay interval. At the same time, however, it will be appreciated that variation of Z in no way affects the previously established condition of the ambient contact separation equalling DM-so that variation of It is an expedient of the desired character for alteration oi the delay interval.

It will be understood that the variations of Z must be between the inherent upper limit of unity, and a lower limit or slightly more than M. But by establishing M (the ratio of the selldisplacement of 9, to that of 3 when R is zero) at a low enough value, a many-times alteration or the delay interval is readily made available. (It may be noted that the traction M/Z in (4), or the value oi M in (2), expresses the fraction of its saturated movement which the lower contact will have undergone at closure. In general, for dependability 01' action, this should be limited at maximum to the general order oi. Thus the minimum value of Z is desirably oi the general order or it of M, under which circumstances the maximum value of the parenthesis term will be or the general order 0! l, and that oi' the log itself of the general order 0! 1.4. If M is approximately the minimum value of the parenthesis term (that is, when Z is unity) will be approximately 1.5, and that oi the log itself approximately .i-providing a Ste-times range of adjustment of delay interval. Smaller values of M than V will provide a corresponding extension or this range.)

My invention embraces not only an electrical expedient for varying the delay interval as already described, but also a mechanical expedient-which, though it may be employed additionally to the electrical means, will usually be employed in substitution therefor (the electrical means then being omitted, as by omitting 49 or maintaining it at zero value). This mechanical expedient consists in the adjustment of the stud i3 longitudinally of the slot la-in other words, in changing mechanically the amount of the selldisplacement oi the electro-thermal device 3-4 11,11 :1 is the fixed spacing of the interval. At the same tim r height ass-mas which is utilized in moving other elements 0! the structure.

Thus let it be assumed that the stud is at any position in the slot. such as that indicated in dotted lines in Figure 1. For each such position there is a respective fraction. 1!. y which the self-displacement oi the electro-thermal device 3-4, as it contributes to the absolute displacements oi l and I and i0 and I from their ambient-temperature positions, must be multiplied. I! z is the variable spacing or horizontal distance of the stud from the righthand side oi the stack contacts from that stack side, and it b is the fixed spacing of that stud side from the elective point oi pivoting action of spring Ii, then it may be shown that approximately x thus varies from unity (when'the stud I3 is under the contacts, and accordingly 3 equals a) downwardly as the stud is moved to the left. The displacements of the several elements from their ambient-temperature positions, taking into account the variable value of x as well as that of Z (which latter may be taken as unity it it is zero), appear in the third vertical tabulation in the corner of Figure 1.

The equation for contact separation, now taking both x and Z into account but otherwise analogous to Equation 1, is

and its solution, analogous to Expression 2, is

Herein it will be seen that variation of X (by movement of the stud ll) just as well as variation of Z (by variation 0! ll) will alter the delay however, it will be appreciated that the stud i3 lies wholly outside the structure formed by the assembly ll-IB- 8-4 and the assembly ll-lli and tie-screw i8; and since it is by previous adjustment wholly within this structure that there was established the condition embodying the criterion abovementioned, the variation of neither x nor Z in any way disturbs this condition. This is true even though there be some accidental alteration of the of the stud accompanying its lateral repositioning, or though the stud is in different instances under thicker or thinner parts of the electro-thermal element 3-4. Thus the variation oi X is a mechanical expedient, oi the desired simple, unitary and foolproof character, for altering the delay interval,

It will be understood that the variations of ZX (or of X itself it Z is unity) must be between the inherent upper limit of unity, and a lower limit of slightly more than M. Indeed, all the remarks of the fourth preceding paragraph as to Z and M, may be taken as applying to Z1! and M (or to x and M, ii Z is unity).

In a general sense, it will be seen that both the electrical and mechanical expedients for al teration o! the delay interval comprise the variation of the degree 0! eilect of the main actuatin device on the contacts, while maintaining unvaried the eflect oi the secondary device thereon. In the illustrated structure it is actually this latter eflect only to which the 01' the contacts has actually absolute adjustment been made, and it is e for this reason that the timing alteration is possible without requiring any absolute readjustment oi the contacts.

As an indication of the non-limitation of the invention to a control means (such as '!8) comprising a normally open switch operated by closure, I have additionally illustrated in Figure 1 a control means comprising a normally closed switch operated by opening at the expiration of the delay interval 01' the system. Thus above the bimetallic arm l5 there may be effectively pivotally supported to the stack 2, for example through light spring 54, an arm 56 carrying on top 01' its righthand extremity a contact 58. This arm 66, which may have a very light net downward bias, may be supported at a fixed distance above the arm HI, as by means of a, vertical rod Bil secured thereto and extending downwardly therefrom and provided with a bottom tip 82 oi insulating material resting on arm iii above contact 8. In turn above the arm 58 there may be effectively pivoted to the stack 2, for example through light spring 53, an arm 55 carrying on the bottom of its righthand extremity a contact 51. The arm 55, which may also have a very light downward bias, may normally bring contact 51 into closure against contact 58. It carries, however, a vertical screw 59 adjustably threaded therethrough Just to the right of contact 51, extending downwardly toward the extremity of arm 9, and provided with a bottom tip 6| of insulating material. The screw 59 may be adjusted so that the tip 6| will just be contacted by the arm 9 when that arm has risen sufficiently to bring contact I into closure against contact 8; and it will be understood that further upward movement of arm 9 will raise the screw 59 and arm 55, carrying contact 51 away from contact 58 and thus opening the switch which those two contacts mutually form, The springs 53 and 54, which of course constitute terminals for the control means 5'l58, may be connected int any suitable circuit (not shown), such as that into which the springs or terminals I i and I2 are connected.

It will be understood, of course, that for any specific purpose it will usually not be necessary t provide two different forms of control means, and that that one only whose use is necessary will ordinarily be provided.

It may be noted that during the bowing of the bimetallic arm 3, the bottom surface of its covering 4a may be forced to slide very minutely on the stud l3. This action, which is purely incidental, is of course entirely without effect while the coupling means is out of operation. And it is likewise without any appreciable eiTect while the coupling means is in operation if it occurs smoothly, without friction-produced jerkiness, and within a region wherein the bottom surface of covering 4a is free from irregularities. It is for this reason that a smooth bottom surface for do is desirable; and an additional precaution to insure absence of frictional eiiects may be taken, if desired, such as the treating of the bottom surface of 4a. with graphite, the use of a proper material and configuration for the top of stud l3, and/or the like.

It may also be noted that it is desirable to have the spring I2, about which the contact 8 effectively pivots, at not too far above the elevation 01' that contactand that that contact must in turn be adjustable to a proper normal proximity to contact 1, as above explained, contact 1 still in turn being desirably not too far above the elevation 01' the spring ii. To meet the above specifications, while aii'ording suitable space for the arm I at the top of the assembly l4-I59 3, it may be desirable to upwardly offset the main portion 01' arm Hi, from immediately adjacent the stack It to near the contact 8.

It may still further be noted that there are a variety of re-arrangements oi the structure of Figure l which will still basically operate in the same manner-some of them serving to eliminate at least one or the fixed arms. In general, however, these last-mentioned re-arrangements will be found to render two or even all three of the bimetallic arms successive in arrangement in the structure, which is undesirable because of unwanted influences oi the temperature of one on another. Accordingly, while no unnecessary limitation thereto is intended, a preference among the possible arrangements is expressed for one like that 01' Figure 1, wherein the bimetallic arms are inherently shielded from each other.

A simplified embodiment of my invention, providing for the mechanical (although not the elec trical) variation of the delay interval, obviates the need for the secondary electro-thermal device (e. g., l5-2l). It still performs the required function of changing the normal relationship between the control member e. g., reducing the normal inter-contact spacing) by an amount dependent on the excess energy of the main actuating device but free of any influence of the adjustment for delay interval. It does so, however, by mechanically deriving and utilizing an appropriate fraction of the self-displacement of the entire main actuating device. Beside its far greater simplicity, this revised embodiment has the further advantage of insuring absolute proportionality at all times between the contactspacing change and the self-displacement of 38-entirely free of the possibility of error in the matching of thermal constants of two separate electro-thermal devices such as 34 and i52l in the first embodiment. Such a simplifled embodiment is illustrated in Figures 2-2a.

In Figure 2 there will again be seen the base I with the adjustable stud I3, the stack 2, the spring ii and the stack I1, and an assembly (whose main components are l69-3) secured to and extending from that stack i1, this assembly being for example entirely similar to that secured to the stack H in Figure 1 excepting for the omission of the arm it. There will also be seen the spring i2 and the arm ID (the latter quite analogous to the arm iii of Figure l excepting that it need have no offset portion) carryin contact 8; this constitutes, in this embodiment. the entire upper assembly insofar as an analogy to the upper assembly i5- |6 of Figure 1 is concerned. (Figure 2, purely by way of non-limitative alternative exampie, shows a modified form of coupling means: when this modified means is employed, it is desirable to retain the upper stack l8 to aid in ts support.)

In this embodiment, there being no electrical delay interval variation, there is no resistance 48, and accordingly the value of Z is unity. The upward displacement of the lower contact I by the electro-thermal device 34 is therefore, for reasons made apparent in connection with Figure 1, dX.

The tie-screw I9 of Figure 1 is of course omitted along with the elements I 4 and I5) between which it was connected. It is replaced in Figure 2 by a tie-screw I9, whose lower portion 19'' (as bestseeninsigurem) isiorexampleinthei rm or a spring hook clasped around the covering do or the heater winding I at a suitable point longitudinally along the bimetallic arm I. The tiescrew I! extends from the hook portion is" vertically upwardly through oversize holes in arm 8 and bimetallic arm (8 and arm It, to carry above the last-mentioned arm the adjustable nut It. The arm I is of course upwardly biased by spring I! (analogously to arm ill .in Figure 1), so that normally the position or arm i0 is determined by the tie-screw l8 and the nut III. a

It may be shown that the upward movement or the arm It at the contact 8 is equal to the self-displacement (oi) oi the electro-thermal device 3-4, multiplied by the traction (X--N) where N is a fraction determined by the longi tudinal position of l9'--l9" along the bimetallic arm 3 and X is as before. In turn it may be shown that it n is the horizontal distance of l!'-l9" from the righthand side of stack l1, and if a and b are as before, then. approximately,

a+b n N: a rt-H) N would thus be unity if the tie-screw i! were at the longitudinal position of the contacts I and I (so that n equalled a). Preferably, however, the tie-screw i9 is so positioned that N is a minor fraction, for example V3.

The upward movements of the elements by the electro-thermal device 3-4, just discussed, have been noted in Figure 2. Since that of the lower that or the upper contact is d(X--N), it will be evident that the efiect of the described arrangement or the tie-screw i9 is to subtract dN from the movement which the upper -eontact would undergo if it were moved by the same means as the lower contact. In other words, the normal inter-contact spacing is reduced by dN-and (IN is a quantity independent of the value to which X may have been adjusted by the positioning of stud I (It is convenient here to note that the consideration just given to the eflect of a self-displacement oi the electro-thermal device 8-4 is valid for displacements produced by a change of ambient temperature. Such displacements are therefore multiplied by X in their eflfect on the lower contact, and by (XN) in their eflect on the upper contact. Now it the self-displacementper-degree-temperature-chanse oi the bimetallic arm lBto which the lower contact I responds over and above its response to s-l-be made equal to N times the self-displacement-per-degree-temperature-change or the bimetallic arm 3, the effect of ambient temperature change on the lower contact will be reduced to identity with the effect on the upper contact, and the device will be quite compensated for variations in ambient temperature.)

By adjustment of the nut 2|) the contact separation (oi contacts 1 and 8) at ambient temperature will be made equal to DNeither by first determining the value of DN and then adjusting the contact separation to equal it when the entire device is at ambient temperature, or by satul'ating the device with the coupling means out of operation and adjusting the contacts to justtouching condition. Then the equation for contact separation becomes similar to (6) above, if therein N be substituted for M and unity be substituted for Z. Accordingly the time required for contact closure, independent of the number 0 cl seconds of any immediately prior operation, and analogous to Expression 2 above, becomes In Figure 2 the conductors 30 and source II and switches 21 and 28 have been illustrated as before, excepting of course for the omission or resistance 48. The conductors 34 from the two control members I and I may oi. course leadtc any circuit to be controlled. such as 32-38 oi Figure 1. Other control means such as 51-58 of Figure l and their associated elements may oi course be incorporated, as schematically indicated by the dotted showings of 59 ,and in Figure 2. And it will be understood that generally the efiective operation of the structure of Figure 2, ineluding not only the closure of contacts I and i but also for example the opening of contacts 50 and ii to obviate overheating oi the device 8-4. is quite similar to that of the structure of Figure 1, so that it need not be re-detailed. Further, as brought out in Expression 9 immediately above, variation of X (preferably within the limits, relative to N, above discussed for its variation relative to M) will serve to adjust the delay interval of the system, for example within a ran e of some 3 times.

As noted above, a specifically diflerent coupling means has been illustrated in Flgure 2 (though it will be understood that the two forms of coupling means are quite interchangeable in all figures). Thus for example the armature 13 oi Figure i may be replaced by a plate lb, biased by the spring 22 into contact with the leithand end surrace a oi. a block ll secured on top of the standard 25 in substitution for the electromagnet 24. To the upper portion of the plate 40 is secured the righthand extremity of a link 42, whose lei'thand extremity is secured in a spool 4! cl insulating material at a short distance from the plate It. From a lower one 0! two lugs it in the stack is a wire 44 is extended rightwardly to reach and pass upwardly around the spool 43 and to extend back to the upper one of the lugs 45. The elements are adjusted so that in the absence of curren flow through the wire ll, it and the link 42 are under tension and hold the plate It slightly spaced from the end surface Ma 01 the blockthe coupling means thus being out oi operation.

The lugs 45 act as terminals for the coupling means, being connected to leads or conductors 2B abovementioned. When these are energized, as by closure of switch 21, the current flow through the wire 44 causes the elongation of the wire; and plate 40, responding to the bias of spring 22, then engages the block end surface lla, placing the coupling means in operation. This action, and the disengagement oi the plate 40 upon current cessation, is characterized by a delay attendant on the finite value of the thermal constant of the wire M. This constant is extremely high (1. e., its time constant is extremely low), however; and the engagement and disengagement oi the coupling means, instantaneous in the structure of Figure 1, remains almost instantaneous in the instant structure.

With the use of separate switches 21 and as for the coupling means and the energy supply to the electro-thermal device, the only practicable arrangements of the heater winding 4 and the coupling means, relative to each other, are eilectively parallel arrangements as illustrated. With such arrangements it may be desirable to employ a resistance such as ll in one of the conductors II to render the voltage reaching the lugs ll an appropriate one for impression across the wire ll. Since the use oi separate switches 21 and is is not necessary tor most typical purposes, however, no unnecessary limitation to a parallel relationship of the coupling means to the heater winding is intended.

Basically the coupling means of Figure 2 is similar to certain of those illustrated and described in the co-pending applications abovementioned, and claimed in the co-pending application Serial No. 336,894. Attention is called, however. to the fact that by the now-illustrated arrangement of securing the extremities of the wire 44 to the stack ll, stresses exerted by the coupling means on the upper-contact-carryin arm II are precluded from altering the bias imparted to that arm by the spring l2.

It will be understood that while the structures so far described are fully compensated for both ambient temperature and prior use, they are not compensated for voltage variation (e. g., for variation 01' the voltage from the source it). Thus the adjustments of the normal relationship between the control members (e. g.. to make the inter-contact spacing equal to DM or DN when the structure is at ambient temperature, or Just zero when the structure is saturated when on coupled) are dependent on the saturation displacement of an electrothermal elementa displacement which varies essentially linearly with watts input-and so are dependent on voltage. According to an important aspect of my invention, this dependence on voltage may be eliminated.

Figure 3 illustrates an embodiment wherein this elimination is eilected in a very simple manner. The structure of Figure 3 may be seen to be entirely similar to that of Figure 2, except that the bimetallic arm II is replaced by a small group of elements which may now be described (and that the offset upper arm I is again employed). These basically comprise a relatively strong leaf spring 88 having its leithand extremity clamped in stack ll very closely above the spring II, and extending from the stack rightwardly for the major portion oi the length of the arm 8; a short, sturdy lug 61 having its lefthand extremity clamped in stack i! above spring 86 and having its righthand extremity for example upwardly curved or bent; and a wire Ill having its respective extremities secured to the righthand lug extremity and to the spring 88 near the righthand extremity of the latter-the wire 68 being held taut by the spring, and the spring being constrained or bowed somewhat upwardly by the wire. The contact 50 (abovementioned as carried by the bimetallic arm is in earlier embodiments) is carried by the spring 68, underneath the point of attachment oi the wire 68 thereto for example.

It will be understood that as the wire 68 elongates and contracts with heating and cooling, the spring 86 will warp downwardly and upwardly, in analogy to the action of the bimetallic arm It in prior embodiments. The displacement-perdegree-temperature-change of the spring 68 (as it influences the contact 1) may be adjusted to the value to which that of the bimetallic arm l6 was adjusted (e. g., to N times the self-dispIacement-per-degree of the bimetallic arm 3), in which event it will be appreciated that the structure will retain the ambient-temperature compensation oi prior embodiments. The adterial oi the wire ll iustment of the displacement-per-degree or spring I! may be eflected by choice oi the maand of the acuteness oi the angle which it makes with the spring 88 (or the spacing of its leithand extremity above that spring). In meeting the requirements of a turther and hereinafter mentioned use of the wire Bl, however, these parameters may happen to be most advantageously adjusted to values which do not provide the desired displacement-per-degree of spring 86. In such an event that displacementper-degree which they do provide may be corrected to the desired one by making the lug ll of bimetallic strip, having a displacement perdegree in its upturned righthand portion 0! suitable value and sign to co-operate with the wire elongation-per-degree in establishing the desired displacement-per-degree oi the spring.

The electrical connection formerly made to the bimetallic arm It now being made to the spring 88, it will be understood that the structure might be employed in an identical manner to that oi Figure 2-the nut 20 being so adjusted that with the structure at ambient temperature the contacts I and 8 are spaced apart by DN, or that with the structure (as so far described) saturated when uncoupled. the contacts I and 8 just touch. Thus as so far described the structure has involved simply a substitution tor the ambientcompensating bimetallic arm I8.

To embody the voltage compensation, however, the structure will be adjusted (by nut Ill) so that, when it is entirely at ambient temperature (the source 3! being temporarily entirely disconnected), the contacts I and 8 will just touch; and thr ughout the use of the structure the spring 88 d contact 50 will be displaced downwardly from their ambient-temperature positions, to provide the normal contact separation, by a distance which varies with voltage proportionately with the variation of the electro-thermally produced displacements in the structure by that voltage.

the heater winding 4.

While obviously current may be passed directly th. ugh the wire 68 to heat it, relative voltage and current considerations may render it more desirable to pass the current through a heater winding about that wire. Accordingly Lhave illustrated (in somewhat exaggerated dimensions, in the interest of clarity) a thin insulating covering 69 for the wire 68, and thereabout a winding ill 01 very fine wirc -the righthand terminal of the winding Hi being for example connected to the spring 66, and the lefthand terminal being connected to a lug ll provided near the top of The spring 66 is already connected to one of the heater-supplying leads 3|] (preferably that one not interrupted by switch 28) and therethrough to one of the terminals of the source 3i. The lug Il may be connected to the other terminal of the source 3|, preierably through a resistance 12.

It will accordingly be understood that the winding ill will be constantly supplied with current (excepting, of course, when the source 3| may be completely disconnected during any long periods of disuse of the system), quite independof the opening and (as contemplated in the illustration of Figure 3) at its saturation displacementand in view of the initial adjustment of the contacts just to touch with the entire device (including wire 68) at ambient temperature, this saturation displacement will be the normal contact spacing. For reasons explained above, this should equal DN (both it and DN varyin but proportionately and so remainin equal. as the source voltage varies). The original choice or parameters of the system. including relative currents through the windings I0 and l, may be so made that this condltion of equality is achieved; it may be desirable, however. to make a final close adjustment, which may be done by adjusting the value or resistance 12 for example. Such adjustment may have as its criterion that the contacts I and I shall just touch when the entire structure is saturated when uncoupled.

It may be mentioned that the voltage-compensating expedient lust disclosed is not limited to a spring-and-wire arrangement such as HI, but may be carried out by appropriately heating any suitably arranged thermal element (such for example as the bimetallic arm ll of prior figures). The spring-and-wire arrangement, however, may be preferred, first because a particularly low wattage input thereto'will serve to provide a suitable degree of displacement, and secondly because its very high thermal constant or low time constant (inherent in view or the extremely low mass of the wire 88) insures its saturation in a very short interval after its initial connection to the source 8i.

Any oi the structures so far described may be employed, if desired, without the arrangements for obviating unnecessary overheating of the electrothermal device 3-4; this may be a particularly desirable simplification when the conditions of use of the structure are such that the current supply to the electro-thermal device or devices is automatically cut off, upon closure of the main contacts l and 8, by some associated circuit action. These arrangements may be eliminated, for example as illustrated in Figure 4, by substituting for the contact 50 a simple push-rod 13 of insulating material adapted to contact the arm therebelow, from which latter contact El and insulation 51 are omitted, and by connecting the righthand extremity of the heater winding 4 directly to the lug 8. From the arm last mentioned there may also be omitted the spring la, the contact I being directly secured to the upwardly offset righthand extremity of the arm; in view of these slight changes the arm has been designated as ii in Figure 4.

Figure 4 also illustrates the incorporation, with a structure of the improved instantly-recycling type dealt with in this application and inthe co-pending applications abovementioned, of a voltage-compensating expedient which in its broadest aspects is disclosed and claimed in my co-pending application Serial No. 344,006, filed July 5, 1940 (which application has eventuated in U. S. Patent No. 2,329,119, issued September 7, 1943). This voltage-compensating expedient differs from that described in connection with Figure 3 in that it obviates the necessity for any part of the structure to be continuously supplied with current-a necessity which would be undesirable in many cases.

According to the voltage-compensating expedlent of the last-mentioned co-pending application, the control members (assuming them to be contacts such as 1 and 8) are normally adjusted so that with the structure at ambient temperature they tend just to touch; and, upon energizatlon of the system, the spacing which the control members tend to assume is rapidly increased by one device which, however. quickly approaches saturation, while another device (the main aotuatins device) is acting much more slowly to reduce it. and does finally reduce it to zero. Means are employed which prevent the contacts from actuallytouchlng normally. these means becoming inefiective (the contacts for example passing out of the range of their effect) by the time the action is partially completed. so that final contact closure is not precluded.

Obviously, devices of the respective speeds of action are respectively constituted by 68-48 and 1-4 in Figure 3; and Figure 4 illustrates a revision ot the structure and circuit of that figure to operate in the manner now under discussion.

Circuit-wise, the only change from Figure 3 (over and above the change already discussed in connection with the omission ofcontacts iii-ll) is the connection of the heater winding Ill so that it is controlled by the switch II along with the heater winding 4 (a by connection of the outer terminal of the resistance 12 to the lead to which runs to lug Ii). structurally there may be added an arm 16, preferably bimetallic, this arm being spacedly interposed between the spring 8' and the arm 0' and having its lefthand extremity clamped in the stack II. This arm 10 may be provided with an oversize hole 18a through which the push-rod 13, abovementioned may operate. Further, near its righthand extremity the arm Il may carry a screw ll vertically threaded through the arm and extending downwardly to have its bottom extremity borne against at times by the arm 9', a little to the left of the extremity of the latter.

With the screw 11 adjusted upwardly sumciently to permit the push-rod 13 to control arm 8', the effect of that screw and the arm Ill are eliminated; and the structure and resistance 12 will be adjusted as last mentioned for Figure 3 (e. g., for contacts just touching, first with the structure all at ambient temperature, and secondly with the structure saturated when uncoupied). Then the screw 'il may be adjusted downwardly to force a normal ambient-temperature separation of the contacts equal to some fraction of the saturation displacement of 65-48 (as referred to contact 'I). It may be mentioned that if the arm 16 be made bimetallic, as preferred. and have a. downward-displaoement-per-degreetemperature-rise (as referred to contact 1) similar to that of 66-68, then any adjustment of the screw 11 will be of similar effect at all ambient temperatures.

When switches I|2il are closed, the spring GB will rapidly move downwardly, carrying pushrod 13 into contact with arm 9'; and in its further downward movement the spring will take over from screw 11 the control of the position of contact 1. Meanwhile the entire lower assembly Bll-68-8-3 is being slowly rocked upwardly about the central portion of spring I l, and final- 1y will bring the contact 1 into closure against the contact 8 (whose arm ill is of course being held stationary by the coupling means). The spring 66. however, will have reached essentially it saturation displacement before this contact closure; therefore fundamentally the contactclosing action of the structure will be seen to be similar to that of precedingly described structures, and to be characterized by the advantages of the operation of those structures. Upon the opening of switches 21-28 the cooling of the wire 58 will rapidly carry the spring 66 upwardly, permitting contact I to rise until the screw 11 again takes over the control of its position. If the upper contact I meanwhile remained stationary. the contact clusure would 01' course continue; but because of the disengagement of the coupling means, and of the rise of nut 20 which has occurred during the closure of the switches IL-Il, the upper contact will spring upwardly upon the opening of those switches, so that dependable and prompt opening or the contacts is insured.

It may be mentioned that the action just described, peculiar to the improved instant-recycling structures of the instant and first-abovementioned co-pending appllcatitons, solves in simple manner the problem of unwanted continued closure of the main contacts after cessation of controlling current supplya problem which is otherwise inherent in the voltage-compensating expedient oi the co-pending application Serial No. 344,006 abovementioned.

It must be noted, regarding such a structure as that of Figure 4 in its normal condition (1. e.. uncoupled. or with the coupling means out of operation) that the contacts I and I just tend to touch when the structure is at ambient temperature (i. e., in terms employed hereinabove, when is zero). Now with increasing values of 1) (representing increasing amount and/or recency of prior use). the lower contact 7 tends to rise more than the upper contact 8, as may be appreciated from the tabulations in Figure 2 for example. So an adjustment of screw 'l'l sufllciently downward to insure normal non-closure of the contacts for low or zero values of v, may be insuflicient at higher values of 0. Indeed, in the extreme theoretical case of v approaching inflnity, the screw 11 would have to have been adjusted so that in an operation of the structure arm 9' would not be carried free of the screw until the device 668B had substantially saturated-and when it was moved away, the arm would be moved for only an infinitesimal distance. The arm must of course be carried free of the screw before contact closure, if the structure is to operate properly. Therefore for more extreme cases or repeated use the proper adjustment of the screw ll becomes increasingly critical, or a higher and higher fraction of the saturation displacement of the device 66-68. Since the latter is dependent on source voltage, the propriety of screw adjustment becomes more and more dependent on that voltage-and this obviously tends to undo the advantage of the voltage compensation. Accordingly the structure of Figure 4 will be most useful in cases wherein more extreme number and rapidity of recyclings do not have to be coped with.

In Figure I show a preferred embodiment of my invention in which voltage compensation is again provided-but simultaneously with the advantage of the Figure-3 embodiment of nonnecessity for critical voltage-dependent adjustments even for most extreme use, and with the advantage oi the Figure-4 embodiment of nonreliance on any indefinitely continued current flow through any part of the structure. At the same time I have incorporated in the embodiment of Figure 5 arrangements for interrupting the supply oi current to the electro-thermal device 3-4 to obviate excessive overheating of the latter, as in earlier embodiments, though it will be understood of course that these may if desired be omitted.

The structure of Figure 5 is basically similar to that of Figure 4. To incorporate the interruption of current supply to 3-4, by way of example in manner slightly altered from that shown in earlier embodiments, I have shown a light lea! spring 85 spacedly interposed between the bimetallic arm 18 and the arm 8'. This spring ll may be lightly upwardly biased from its lei'thand extremity. which is clamped in the stack ll, so that it at all times bears upwardly against the bottom 01' either screw II or push-rod I3 (according to the thermal condition of the wire it). The spring I! may extend to a little beyond the screw 11, and on the bottom of its righthand extremity may be carried the contact 50 or earlier embodiments; the spring 85 may electrically be connected to lug 8. 0n the arm immediately below the contact Ill may be insulatedly carried the contact I" of earlier embodiments, electrically connected to the righthand extremity of the heater winding 4.

It will be understood that by reason oi the upward bias of arm 9', contacts 50 and II will always touch each other excepting when the lower assembly is further upwardly rocked alter the main contacts 1-8 have closed. To obviate the immediate opening or contacts "-6! upon main contact closure (as was done screw 11 and push rod ls-for example to bottom on an insulating stop button 86 carried on top oi arm 9 underneath the push-rod. During the early upward movement of the lower assembly after main contact closure the contacts ill-8i will remain closed until the spring 85 has recovered from the yielding just mentioned, and only thereafter will they open to interrupt the supply of current to the heater winding 4. So long as the main contacts l8 are open, and accordingly either the screw 11 or push-rod II is establishing the position of contact I, the spring 2: will be kept yielded against the stop button The heating circuit for the wire 68 (e. g., the winding 10) may be connected basically as in Figure 3 (i. e., through source 3|,

Such a switch is conveniently formed by a contact 78 carried on top of the righthand extremity of the bimetallic arm 16, and a contact I9 carried on the bottom of the righthand extremity of a leaf spring so thereabove, the lefthand extremity of spring 80 being secured in a miniature stack 8| held to the bottom of the arm Ill just to the right of the tie-screw IS. The ambientternperature spacing of the contacts "-19 being made very small. and since the extremity of the bimetallic arm 16 moves upwardly according to (ix while the arm I 0 can move upwardly only according to (X-N), it will be understood that when the electro-thermal device 3l has any significant excess temperature over ambient (l. e., when d is anything above a very small value) the contacts 10-19 will be closed. The

movements of the structure it should be made extremely light.

The switch ll-II may be with the heater winding 1| by connecting the spring 80 (as through lug .2 in stack II) to the resistance 12. and by connecting the spring to the bimetallic arm II. Since this bimetallic arm is now connected into circuit non-coincidently with the spring II, the screw 11 carried by that arm should be insulated thereirom, as by the insulating bushing 'llb seen in Figure B.

In initially adjusting the structure of Figure 5. the source It will be entirely disconnected, the screw II will be backed oi! upwardly so that pushrod 18 controls the position of contact I. and. the entire structure being at ambient temperature, the nut 28 will be adiusted so that the main contacts 1-! just touch. Then the entire structure may be saturated. with the coupling means "-42 out oi operation (c. g.. with switch 2. closed and switch 21 open), and resistance ll adjusted so that the main contacts again Just touch. Finally, with the structure again at ambient temperature, the screw 11 may be adjusted downwardly to eiiect an arbitrary spacing oi the main contactsior example, to about half oi the saturation displacement undergone at average source voltage by the electro-thermal device "-8! (as reierred to the main contacts).

In any operation starting at ambient temperature (the contacts 18-18 accordingly being initially open), closure of the switches 11 and is will first be followed by an upward rise of contest I irom its position arbitrarily established as abovementioned. But aiter there has elapsed a very small fraction of the delay interval oi the system (a fraction which will vary with source voltage, but will remain very small throughout variation of that voltage through a very wide range), the contacts II-48 will be closed. The electro-thermal device 66-48 will thereupon go into operation. and will very quickly move the spring 85 downwardly away from the screw 11, thus taking over the control of the lower contact position. By the expiration of the delay interval the device 58-68 will have essentially saturated, thereby establishing the proper, voltage-controlled relationship of contacts I and 8- a relationship equivalent to their normal ambient-temperature separation by dN-in time for that relationship to exist at their closure. This action is entirely similar to that oi the Figure-4 structure, excepting for the very slight postponement of inception of heating and action oi the device BB-JB-permissible since its thermal constant is high enough (i. e., its time constant low enough) so that it essentially saturates in the very major fraction of the delay interval remaining after closure of lit-I8.

Unless the structure is permitted to cool back essentially to ambient temperature, the contacts 1s-1s will remain closed, so that in re-cvclings of the system it will act like that of Figure 3in which the current supply to 66-68 was maintained continuously. But the indefinite continuance of current supply in the structure of Figure is obviated-since after any last use of the system, the device 3-4 will return to ambient temperature, opening the switch formed by 18-19 in the last portion of that return.

It may be noted that this switch is ambientstated to be preferred in Figure 4, the downward displacement-per degree-temperature-rise oi the bimetallic arm IB be similar to that of the electrothermal device "-48, and if, as stated to be preferred in connection with Figure 3, that dissrrsnsfl inserles ticularly disclosed for placement per-degree oi "-4! be H times that of the electro-thermal device 3-4 (all these displacements being reierred to the main-contact position).

It may be re-emphasized that the structures oi each oi Figures 3. 4 and 5excepting for the manner in which'and time; at which the Pr p r inter-contact relationship is established and ior the attendant diflerences in manner oi initial adiustment (and in Figure 4 for the omission oi the interrupting means ior heater winding 4)- operate basically like the structure oi Figure 2, with delay interval established, as indicated in Expression 9 above, by the value oi X as determined by the position oi stud it.

It will be observed that the structure oi Figure ii may be operated. if desired, with the spring ll bent to keep the contacts II and is closed against each other even when the device 1-4 is at ambient temperature, in the manner disclosed for the operation of Figure 3.

It will be appreciated that the structure; parestablishin: the motion of one oi the control members (e. g., 'l) at a variable (x) times the self-displacement oi the main actuating device is. 3., 8-4), and for dcrivini a iraction (N) of that sch-displacement for subtraction from that motion to establish an appropriate motion of the second control member (e. g., I) when uncoupled. take advantage of the arcuate manner in which a bimetallic arm displaces itself with heat. They iorm means for establishing these motions which not only are simple, but also are readily adapted to the variation of X ior delay interval variation without attendant influences on other adjustments of the structure, and they are preferred on those accounts. It is, however, to be understood that many of the aspects of my invention entirely transcend these particular structures and means, and are incorporable in structures and systems very difierent in respect oi the support and arrangement of the actuating or energy-storing devices-and even in respect of the nature of those devices, which obviously need not be bimetallic arms ior all purposes.

It will be understood, as has been made apparent in the earlier figures hereof, that while the principal description has been most conveniently presented in terms of control members comprising normally open contacts intended to be operated by closure against each other, no unexpressed limitation thereto is intended-nor is there intended any such limitation even to control means comprising contacts, for obviously the control means may comprise any plurality oi members to be operated by a relative movement.

Further, it may be pointed out that the compensations for prior use hereinabove described have been presented on the assumption that a full such compensation would be desired-in other words, that there shall be no appreciable shift of delay interval in the case of quickly repeated operations of the system. There may, however, be certain instances of use wherein there is desired a definite shift of interval in such cases. In wholly conventional systems there is an extreme such shift in a negative direction (i, e., shortening of the delay interval), while in the improved systems disclosed in the co-pending applications Serial Nos. 336,873 and 336,894, there is some such shift in a positive direction (i. e., lengthening oi the interval). By shifting the relationship between the control members one way or the other from those above mentioned as preferred. there may be provided a shift of interval with repeated operations, in either direction and of any desired degree.

It has been pointed out in the co-pending applications above mentioned that while the operation contemplated for the usual case involves the simultaneous supplying of energy to the storing device (e. g., of current to the winding 4 on bimetallic arm I) and operation of the coupling means, there is contemplated for special cases the use of the system with these functions separately controlled-e. 8.. with the omission of the insulating tie 29 between the switches 21 and 28. In such a case broadly, the control means (e. g., 1-8) will be operated when, during any period of coupling-means operation, the energy supplied to the storing (e. g., electro-thermal) device less any losses therefrom (whether the energy supply be continuous or intermittent) has reached a predetermined value-the switches (e. g., 21 and 28) respectively controlling that operation and that supply being controlled appropriately to the ultimate function for which the system is employed. It is to be understood that broader aspects of the instant invention contemplate such separate control, and that the invention is capable of eilecting improved results therewith analogous to those it effects in the case of simultaneous control.

As brought out hereinabove, there is intended no limitation in respect of the forms of coupling means in particular embodiments, as there are obviously interchangeable the two particularly disclosed means as well as others.

Certain features of my invention are without limitation to structures of the improved instantly-recycling type. One may be mentioned in particular-the feature (illustrated in Figure'5) of voltage compensation by a device continuously supplied with current so long as the main actuating device is at appreciably over-ambient temperature. This may be incorporated in a simple (i. e., non-instantly-recycling) structure which is to be voltage-compensatedsuch as I have contemplated in my co-pending application Serial No. 344,006, Patent #2,329,119, Sept. '1, 1943, above mentioned-and serves therein, among other things, to insure a normally prompt opening of the contacts from each other (for which other expedients were disclosed in that application). 1 have illustrated such an incorporation in Figure 6 hereof. In this fi ure there has been included the feature of interruption of the heater current supply to the main actuating device after operation of the control means, to obviate excessive overheating of that device, though it will be understood that the structure may be simplifled by the omission of this feature when desired in cases wherein it is not considered necessary.

In Figure 6 a single stack ii 1, secured for example to base I i, may serve to support all the elements. The lower portion of the structure may comprise arm ll, spring 85, bimetallic arm 16, spring 86 and wire 68. and lug 1lall with their respective immediately associated components, and in the same mutual arrangement, as in Figure 5. Thereabove may be provided the arm llll, analogous to arm ill of Figure 5 excepting that it is assembled to the same stack H1 through spring III by which it is upwardly biased. The arm iill carries the same elements as did arm ill in Figure 5, one of these being the spring 80 whose electrical connecting lug 82 may be clamped in the stack in underneath spring :12. Above the arm liil there may be provided the bimetallic arm it, its lefthand extremity clamped in the stack 1. A screw I20 may be adjustably threaded downwardly through the righthand extremity of bimetallic arm lill: and a piece i2lla of insulating material carried on top of arm liil may bear upwardly against the bottom of this screw, so that the screw serves to adjust the position of that arm relative to the bimetallic arm i 03. A heater winding iill may be provided about the bimetallic arm I", its electrical extremities being connected analogously to those of the winding I in Figure 5-1. e., one to the contact 5i and the other to lug 5, which in this instance may be near the top of stack 1. With heat the bimetallic arm lill may bow downwardly at its righthand extremity, similarly to the bimetallic arm 16 and to the electro-thermal device 88-88: and its displacement-per-degree-temperaturechange may be similar to those of 16 and 8648 (all as referred to the position of the main contacts 1 and I) Electrically, one terminal of the source 3| will be connected through the switch 28 to the lug i, and directly to the lug 82, for current supplies respectively to windings I04 and 10. Since the structure is not arranged for instant recycling, there is no requirement for a careful adjustment of the saturation displacement of 86-68 to make it equal some function of that of the main actuating device HIS-I64; it is only necessary that the former remain an appropriately low fraction of the latter. But, as brought out in my copending application Serial No. 344,006 abovementioned, a control of the relative displacements of those two devices, by control of relative watt inputs thereto, serves to control the delay interval. Accordingly the connection of the other terminal of source ii to the spring 85 and lug 1i, instead of being direct, may be made through a variable resistance arrangement typically compising a resistance I12 connected between 1! and I5, and a variable contact l12a movable over the resistance element and connected'to the source terminal. Bimetallic arm 18 will of course again be connected to spring 66. Finally, to connect the control members (contacts 1 and 8) into any circuit to be controlled (such as 32-38 of Figure 1), leads 34 may be employed, respectively connected tosprlngs ii and H2.

The structure of Figure 6 will be initially ad- .iusted with the source 3| entirely disconnected and with the entire structure at ambient temperature and with the screw 11 backed on upwardly so that spring 66 controls the position of contact 1. Under these circumstances the screw (III will be so adjusted that contact 8 Just touches contact 1. Then the screw 11 will be adjusted downwardly to establish an arbitrary normal spacing of the contacts. As in the case of Figure 5, spring will be so bent that with the structure at ambient temperature there will be a very slight separation of the contacts 1819.

The operation of the structure of Figure 6 is probably most easily understood herein as a simpliiication of that of Figure 5, appropriate to the omission of the instant-recycling, or prioruse-compensation, feature. The contact 1 is still subjected to control by the device 86-88 when that device is heated, as in Figure 5. The main actuating device, instead of moving the contact 1 (and contact 18) upwardly toward contact 8 (and contact 19). moves the latter downwardly toward the former; but the relative contact started at substantially tact i will close against movements will bennderstood to be entirely similar tothose inFigure while the coupling means thereor is in operation. In view of the simpliiied nature or the structure, it will 01 course operate with the intended delay interval only when ambient temperature. In initial part or the operation, iollowing switch I8, contacts It-ll will be against each other, and the heated and will rapidly Meanwhile the very closure 0! brought into closure device "-4! will be carry contact I iurther downwardly.

contact 8 is slowly moving downwardly; and at.

the expiration of the delay interval determined by adjustment or the contact Illa on resistance element "2, and entirely independent of wide variations in the voltage from the source ll, concontact I. Thereafter a slight further downward movement of contact 8 will have carried the arm I sumciently downwardly to open contacts I l89, tor the obviation oi excessive overheating or Its-4M, as will be understood. Upon the opening of switch 28 the contact 8 will move upwardly; but contact I, since the supply of current to the device "-8! is for the present continued. will be held in its downwardly displaced position-so that there is provided the same contact-separating action as in wholly conventional structures. When, and only when, the device llIl-IM has returned to substantially ambient temperature, the contacts "-1! will be opened to cut oil the supply of current to the device 06-".

While I have illustrated my invention in terms 01' particular embodiments thereof, and with features variously grouped in the several embodiments, it will be understood that the details or and groupings within those embodiments are in many instances illustrative or typical, rather than limitative, and that wide modifications thereof may be made without departing from the spirit or scope of the invention.

I claim:

1. In an electrical control system including relatively movable control members and operable by the establishment of said members in a particular mutual relationship, said members being adjusted to normally tend to assume substantially that relationship: the combination of an elec-' tro-thermal device energizable to effect a relatively slow displacement or one of said members; an electro-thermal device adapted upon energization to effect a relatively rapid displacement of one of said members. toward a saturation value less than that of the first-mentioned displacement, and in direction opposite to the first-mentioned displacement in respect 01' relative member movement; means blocking the establishment of said members in said particular mutual relationship when the flrst'recited device is at or near ambient temperature; and means for energizing the second-recited device whenever the first-recited device is at a temperature appreciably above ambient temperature.

2. In an electrical control system including relatively movable control members and operable by the establishment of said members in a particular mutual relationship, said members being adiusted to normally tend to assume substantially that relationship: the combination 0! an electrothermal device energizable to eflect a relatively slow displacement oi-one of said members; an electro-thermal device adapted upon energiaation to effect a relatively rapid displacement oi! one of said members, toward a saturation value less than that oi the first-mentioned displacement,

and in direction opposite to the first-mentioned displacement in respect of relative member movement; stop means {or holding said last-mentioned one member partially displaced in the absence of its further displacement by the second recited device; and means for energizing the seeond-recited device when the first-recited device is at a temperature appreciably above ambient temperature.

3. In an electrical control system including relatively movable control members and operable by the establishment oi said members in a particular mutual relationship, said members being adjusted to normally tend to assume substantially that relationship: the combination of an electrothermal device energiaable to elect a displacement of one of said members; an electro-thermal device adapted up n energization to eilect a displacement of one or said members, to a saturation value, and in direction opposite to the firstmentioned displacement in respect of relative member movement; and means for maintaining the second-recited device continuously energized throughout periods oi'possibleuse oi-the system.

4. In an electrical control system including relatively movable control members and operable by the establishment of said members in a particular mutual relationship: the combination or an electro-thermal device energize-hie to move one of said members for operation of the system; and means, comprising a continuously energized electro-thermal device, for establishing, in accordance with the voltage at which current is supplied to the system, the distance through which said last-mentioned member must be moved to establish said relationship.

5. In an electrical control system including relatively movable control members and operable by the establishment of said members in a particular mutual relationship: the combination of an electro-thermal device energiaable to move one of said members for operation of the system; electro-thermal means energieable to establish. in accordance with voltage at which current is supplied to the system. the distance through which said last-mentioned member must be moved to establish said relationship; and means for energizing said electro-thermal means whenever said electro-thermal device is at a temperature appreciably above ambient temperature.

6. In a control system including relatively movable control members characterized by an initial mutual relationship and operable by the establishment of said members in another mutual relationship: the combination of an electro-thermal device suppllable with cunent, for moving one of said members to operate thesystem; and mechanical means for altering the degree or movement of said one'member by said device, whereby the interval of current supp y required for operation of the system may be varied without alteration of the amplitude of current supply or or said initial relationship of said members.

7. In a control system including coasting movable control members: the combination of means for effecting a movement of a first 01' said memthereof; a second support for said arm at a distance from said extremity; a control member responsive to the displacement of a point on said arm; and means for varying the point of said second support longitudinally along said am to vary the response of said control member to said 10. In an electrical control system including coacting movable control members: the combination of a heatable bimetallic arm having, as a first support, means pivotally holding one extremity thereof; a second support for said am at a distance from said extremity; means rendering one of said control members responsive to the angular movement of said arm extremity; and means rendering the other of said control members responsive to the displacement of a point on said arm.

11. The combination according to claim 10, further including means for varying the point of said second support longitudinally along said arm, whereby to vary the responses of the respective control members to said arm while maintaining substantially constant the difference between said responses.

12. In a control system including coacting movable control members and coupling means operable to influence one 01' said members; the combination or means maintaining said members in predetermined mutual relationship when said coupling means is out of operation; an electro-thermal device energizable to move one 01 said members; and mechanical means, included in said maintaining means and responsive to said device, for causing said mutual relationship to be predetermined in accordance with the temperature of said device.

13. In a control system including coacting movable control members and coupling means operable to influence one of said members: the combination of means maintaining said members in predetermined mutual relationship when said coupling means is out of operation; an energystoring device whose energy content may be changed, for moving one of said members in accordance with changes in said energy content; and mechanical means, included in said maintaining means and responsive to said device, for causing said mutual relationship to be predetermined in accordance with said energy content.

14. In a control system including coacting movable control members and coupling means operable to retain one oi said members against movement: the combination of an electrothermal device for eifecting a movement of the other said member; and mechanical means, responsive to said device and efiective when said coupling means is out of operation, for efiectlng a movement of the first-mentioned member proportionate to but smaller than the movement of the second-mentioned member.

15. In a control system including coacting movable control members and coupling means operable to retain one of said members against movement: the combination of an energy-storing device whose energy content may be changed, for moving the other of said members in accordance with change in said energy content; and mechanical means, responsive to said device and eil'ective when said coupling means is out of operation, for eflecting a movement or the firstmentioned member proportionate to but smaller than the movement of the second-mentioned member.

16. In a control system including coacting movable control members and means normally maintaining said members in predetermined mutual relationship, said system being operable byestablishment of said members in another mutual relationship: the combination of coupling means operable to render said maintaining means inoperative; an electro-thermal device, energizable during operation of said coupling means, for moving one of said members for operation oi the system; and means, rendered effective by the continued energization of said device after operation of the system and while said coupling means remains in operation, for de-energizing said device.

17. An electrical control system operable with a delay interval compensated both for prior uses of the system and for the voltage at which current is supplied to the system, comprising, in combination, coacting control members, cou- Dling means effective on one of said control members, electro-thermal means for varying the mutual relationship between said control members in greater and less degree when said coupling means is respectively in and out of operation, and independent electro-thermal means displaceable to essentially a saturation value for varying the mutual relationship between said control members additionally in accordance with said voltage.

18. In -an electrical control system including a mounting member and a biased member extending in cantilever therefrom: the combination of a heatable wire extending to said mounting memberirom a remote point on and at an angle to said biased member, for holding said biased member displaced against its bias by a temperatureresponsive displacement; and bimetallic means, thermally moved in the longitudinal direction of the wire, for securing the wire to the mounting member.

19. In an electrical control system including a mounting member and a biased member extending in cantilever therefrom: the combination of a wire heatable by current, extending to said mounting member from a remote point on and at an angle to said biased member, for holding said biased member displaced against its bias by a temperature-responsive displacement; and means securing the extremity of the wire to the mounting member, comprising an element characterized by temperature-responsive movement in the longitudinal direction of the wire, whereby the biased member will be displaced by diflerent amounts per degree of temperature change 01' the wire caused by current, and per degree of ambient temperature change.

CHARLES 'I'. JACOBS.

Certificate of Correction Patent No. 2,367,028; January 9, 1945.

CHARLES T. JACOBS It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 29, for restored read resorted; page 6, first column, line 23, and second column, line 34, for that portion of the equatlon v+t read 0+1; page 8, second column, line 48, for "curren, read current; p e 11, first column, line 12, for applicatitons reed applications; page 13, second co umn, lines 42-43, for "compising, read comprising; and page 15, first column, line 10, claim 9, for 011", read one; and that the said Letters Patent should be read with these corrections therein that the samemay conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of August, A. D. 1946.

LESLIE FRAZER,

First Assistant Commissioner of Patents. 

